Note: "WHY IS MATT A WOMANIZER?" This question was posed in the 'Why Meme' at CnC, and my answer ended up being incredibly tl;dr. However, I didn't fully touch on all the points I wanted to make on the subject, so I've decided to expand on my answer to the question here. For now I am posting my first response, and once I've written out the other points, I'll be adding them to this post.
I've based my answer and my interpretation on canon as best I can, but I feel that character interpretation also depends on the writer. So while this is based on events in the comics, it's also colored by how I see the character and think he should be portrayed. So, consider this a head's up, and enjoy!
I wouldn’t really term him a womanizer... that word has more negative connotations than I’d really associate with his relationships. He’s more of a serial monogamist who has slipped up on occasion. While he does have a long string of romantic entanglements, and he hasn’t always been the most faithful of partners, he doesn’t actually actively pursue other women while he’s in a committed relationship, and he really doesn’t sleep around as much as his reputation would suggest. Going through his canon with a friend recently, we came up with eleven confirmed girlfriends/whatever term you prefer, and while there are a few in there that were very short-term flings (i.e., one-night stands) the vast majority fall into the long-term-at-least-semi-committed type of relationships.
The main issue that Matt has to deal with though is rejection and abandonment, and I think a lot of it stems from mommy-issues. Cliche answer, I know, but I think that is really the root of it. He was abandoned by his mother a birth, and even though he had assumed she was dead, that planted the seeds of what was to come with how he interacts with women. He really lacked any female influence in his life as a child. He was raised by a hard-drinking Irish Catholic boxer, and while he wasn’t regularly abused or anything, his father did hit him, and with no one to counteract the dynamic of their relationship, he was left constantly seeking someone to comfort him, someone to latch onto.
But that also warped his perception of feminine roles. He grew up craving someone maternal, someone to take care of him and nurture him. He seeks that out, he really does, but after time, these relationships seem stagnant and he finds himself sexually drawn to dangerous, strong, often dominating women. It’s a variation of the Madonna-whore complex when you get down to it. He wants to be loved, but he doesn’t get fulfillment from the good girls who stay at home and bake cookies. He needs that spark, he needs the excitement, and more often than not, he cannot find both of those qualities in the same woman.
So you take a look at the women he’s been involved with. Elektra, for example. Initially, she is portrayed as the sheltered-daughter of a diplomat, gentle, good natured, kind. She fit in very nicely with the maternal Madonna-figure that he craved. Until her father died and she left him, of course. That rejection was a major blow to him. He was young, she was his first love, and indeed his first lover, and her rejection really set the tone for things to follow. Remember too that he wouldn’t encounter her as an assassin for many years, so it’s not until later that she’ll fit the dangerous/dominating profile.
Then you have Karen... and, well, that’s a whole new can of worms. Karen was a nice girl, a good girl. She was sweet, caring, pretty much the ideal for any Catholic man. For the longest time, the writers seemed to force the Matt/Karen/Foggy love triangle, and Matt was particularly obsessed with the fact that he would inevitably be rejected by Karen because he was blind. Indeed, Karen would say some pretty callous and not at all PC things about him and his blindness, and yeah, I get that the 60’s were a different time and the being sensitive to disabilities wasn’t totally mainstream, but they really played up the fact that the main thing preventing Matt and Karen from living happily ever after was the fact that he couldn’t see. Matt was so certain that Karen would reject him that for months he didn’t even bother trying to woo her. He just cut to the chase and grieved the loss of the relationship before it even began. Anyway, they eventually get together, engagement occurs, and the relationship falls apart due to both parties not being completely faithful to each other. Matt isn’t the innocent party in this by any means, considering how it all went down, but Karen’s infidelity is played up more than his is, in that she is portrayed as having cheated on him first. Not that this should excuse anything, but Karen’s rejection is just another blow to his poor tormented little psyche, and it made his falling into bed with Black Widow more justifiable, in his mind.
Natasha falls into the second category of women. She’s excitement, adventure, and really, the complete opposite of what Karen Page was up until that point. And their relationship was chaotic and volatile and fun. Natasha was definitely in charge of the relationship, she called the shots, and she determined when she was through with him. And of course she would eventually be through with him. Even though she wasn’t the maternal type of woman he craved in his earliest romantic relationships, her rejection stung him a great deal. Being dumped by a strong female like Natasha shifted how Matt perceives women. He wants to be the man, he wants to be in control. His subsequent relationships with “nice girls” are support this. He was manipulative to the maternal, caring types, meanwhile finding outside fulfillment with women like Natasha, Elektra, Typhoid Mary, etc.
Coming Soon/To Be Expanded On...
Elektra's return, manipulation of Heather Glenn, Karen's fall from grace/manipulation, marriage to Milla, why he should never have gotten married... any other points that may cross my mind.